You can ignore all of this and create something that will render on a small screen, and say your mobile site is "done" but to do so is to miss out on the opportunities that mobile web presents. Doing this right is much harder of course, but there's a reason why almost all of the Alexa top 100 sites serve entirely different HTML to mobile devices, rather than taking a media queries approach.
There's a summary of all the ways to achieve these goals here: http://mobiforge.com/starting/story/mobile-web-content-adapt...